Coke oven comprising tertiary heating elements in the gas chamber

ABSTRACT

The invention relates to a horizontally designed, non-heat recovery-type coke oven comprising at least one coking chamber, downcomers that are laterally disposed relative to the coking chamber, and bottom ducts which are horizontally arranged below the coking chamber in order to indirectly heat the coking chamber. One or more heating elements are located in the gas chamber which is not filled with solid matter when the coke oven is appropriately used.

The invention relates to a coke oven of horizontal construction (non-recovery/heat recovery type) consisting of at least one coking chamber, laterally arranged vertical downcomers as well as bottom flues arranged horizontally and extending underneath the coking chamber for indirect reheating of said coking chamber, wherein one or more heating elements are arranged in the oven free space which in the intended operation of the coke oven is not destined for being filled with solid matter.

Coke ovens of horizontal construction are known from prior art in technology and they are in frequent use. Examples of such coke ovens are described in U.S. Pat. No. 4,111,757, U.S. Pat. No. 4,344,820, U.S. Pat. No. 6,596,128 B2 or DE 691 06 312 T2.

Known from prior art in technology are different approaches designed to speed up the coking time of coal and to assure a uniform advance of coal carbonisation in the coal charge or stamped coal cake.

The approach strongly pursued here was to improve gas routing in the oven room. In DE 10 2005 055483 it is proposed to automate the air feed which is accomplished through the oven doors and to control it depending on the coking time through a central drive. Even though a good controllability is thereby achieved, the problem still exists of supplying the depth of the oven room evenly with combustion air without unnecessarily increasing the burn-off in the area near the oven door too much.

DE 10 2005 025955 proposes a multiple feed of combustion air which is realised through a distribution system that is mainly arranged on the oven top. Through this distribution system, combustion air is conducted from above through the oven top via many openings into the oven room. This system of feeding combustion gas represents a marked improvement versus a central introduction of combustion air through openings in the oven door. Still there is a demand, however, to further improve the gas routing in the coke oven and to reduce the coking time, thereby improving the economic efficiency of this method.

This task is solved by the coke oven of horizontal construction (non-recovery/heat recovery type) as defined in the principal claim. This coke oven consists of at least one coking chamber, laterally arranged vertical downcomers as well as bottom flues arranged horizontally and extending underneath the coking chamber for indirect reheating of said coking chamber, wherein one or more heating elements are arranged in the oven free space which in the intended operation of the coke oven is not destined for being filled with solid matter.

The heating elements may have any form and are ideally shaped as hanging ribs or hanging walls, which can be further improved to have openings or a partly open structure.

In principle the heating elements can be fastened in any kind in the oven chamber. Ideally the tertiary heating elements are detachably hung into suitable holders, with these holders being mounted in the wall and/or top of the coking chamber. On the one hand it has the advantage that the tertiary heating elements can be taken out more easily when work is to be done on a coke oven chamber, and on the other hand it is avoided in this manner that expansion processes are transferred into the oven brickwork.

Another improved variant of the coke oven lies in adapting the gas routing to the positioning of the heating elements. Thus, when the coking chamber is section-wise divided by the heating elements, at least one air feeder mains is led into each of these sections and one or two downcomers are led out from each of these sections.

An improved variant of the coke oven lies in that at least part of the interior walls of the coking chamber and/or part of the surfaces of the heating elements is configured as secondary heating surfaces by coating them with a high-emission coating (HEB), with the emission degree of this high-emission coating being equal to or greater than 0.9.

This HEB preferably consists of the substances Cr₂O₃ or Fe₂O₃ or of a mixture containing these substances, with the portion of Fe₂O₃ amounting to at least 25% by wt. in a mixture and with the portion of Cr₂O₃ amounting to at least 20% by wt. in a mixture. Alternatively, the HEB can also contain SiC with a portion of at least 20% by wt.

In an improved variant of this coke oven, the HEB furthermore contains one or more inorganic binding agents. It has also been found that the constituents of the HEB should have a special grain size which is smaller than or equal to 15 μm and which ideally ranges between 2.5 and 10 μm.

By way of the HEB, the radiation situation in the coke oven room is substantially improved and the fast coking process from top to bottom is further speeded up.

The coke oven can be further improved by coating the walls of flue gas channels extending horizontally underneath the coking chamber partly or entirely with HEB in any one of the material composition as described hereinabove, thus improving the indirect heat transport through the floor of the coke oven chamber.

Also covered by the present invention is a method for production of coke by implementing the coke oven described hereinabove, utilising one of the embodiments. In general, a multitude of the described coke ovens are then operated more or less in parallel.

According to a particularly suitable variant of the method it is provided that the temperature in the coking chamber during the coking process ideally amounts to 1,000 to 1,400° C. on average. This temperature may also be exceeded for a short period of time.

FIG. 1 shows the inventive coke oven in a sectional view. The coke oven 1 consists of an oven top 2, oven walls 3 and an oven floor 4, which enclose the oven room 5. The air feeder mains 6 represented in dashed lines lead into the oven room 5. The coal charge 7 rests on the oven floor 4 and flue gas channels 8 extend underneath the oven floor 4. Also shown in the cross-section are the air feeder mains 10 provided in the oven foundation 9 which allow for conducting air into the flue gas channels 8.

Through vertical downcomers 11, which extend in the oven walls 3 from the oven free space of the oven room 5 to the horizontal flue gas channels 8 underneath the oven floor 4, the gases developing during coal carbonisation can be discharged.

The interior surfaces of the oven room 5 are provided with an HEB that consists of Cr₂O₃, Fe₂O₃ and SiC in equal portions. This HEB of the interior walls, thereby becoming secondary heating surfaces, has not been shown here any further. Furthermore, heating elements 12, tertiary heating surfaces, are mounted in oven room 5 vertically and parallel to each other which, by and large, fill the free cross-section above the coal charge 7 and which are also coated with this HEB. The heating elements 12 are mounted to the holder elements 13 which in the case shown here have a shape of wall and roof anchors. In the example shown here, a small, circumferential gap 14 is left between the interior wall surfaces of the oven room 5, coal charge 7 and the outer edge of heating element 12 in order to allow for a horizontal convection in the oven room 5 and to prevent damage to material due to differences in the expansion behaviour of the structural parts.

FIG. 2 shows the inventive coke oven 1 in another sectional view. The reference symbols of FIG. 1 apply analogously. What can be clearly seen is the division of the oven room 5 through heating elements 12 into six sections, with air feeder mains 6 leading into each section and wherein gas can leave the oven room 5 again through openings 15 and flue gas channels 8 as well as downcomers 11. The introduction of combustion air into the oven sections which are adjacent to the oven door 16 is accomplished through air feeder mains 6 which are provided in the oven door 16 proper. The heating elements 12 are mounted to the holder elements 13 which are provided in the oven top 2 and oven wall 3 for this purpose.

In a sectional view, FIG. 3 represents a special suspension for heating elements 12, showing the section of coke oven 1 which lies adjacent to the oven door 16. The heating element 12 hanging in oven room 5 is spaced from coal charge 7 with a gap 14. The heating element 12 is fastened through one or several holding elements in the oven top 2. This holding element mainly comprises a top plate 17, a pull bar 18 and a bottom plate 19. The pull bar 18 is plugged through a top opening 20 and is held by the top plate 17 which simultaneously closes the top opening 20 entirely. Furthermore, the pull bar is guided from the top to the bottom through the heating element 12 and/or built-in into said heating element. The main weight of heating element 12 rests on the bottom plate 19 of the holder element fastened to the bottom end of the pull bar 18.

By way of this division of the coke oven into various sections with a section-wise gas routing and by way of the homogenisation of radiation through the heating elements, it was managed to reduce coking time and to minimise losses of product in the area close to oven doors.

LIST OF REFERENCE NUMBERS

1 Coke oven

2 Oven top

3 Oven wall

4 Oven floor

5 Oven room

6 Air feeder mains

7 Coal charge

8 Flue gas channel

9 Oven foundation

10 Air feeder mains

11 Downcomer

12 Heating element

13 Holder element

14 Gap

15 Opening

16 Oven door

17 Top plate

18 Pull bar

19 Bottom plate

20 Top opening 

1-12. (canceled)
 13. A coke oven of horizontal construction (non-recovery/heat recovery type) comprising at least one coking chamber, laterally arranged vertical downcomers as well as bottom flues arranged horizontally and underneath the coking chamber for indirect reheating of said coking chamber, wherein one or more heating elements are arranged in the oven free space which in the intended operation of a coke oven is not destined for being filled with solid matter.
 14. The device according to claim 13, wherein the heating elements are shaped as hanging ribs or hanging walls, and that said tertiary heating elements may have openings or a partly open structure.
 15. The device according to claim 13, wherein the tertiary heating elements can be detachably hung into suitable holders, with these holders being mounted in the wall and/or top of the coking chamber.
 16. The device according to claim 13, wherein with a section-wise division of the coking chamber by the heating elements at least one air feeder mains leads into each of these sections and one or two downcomers lead out from each of these sections.
 17. The device according to claim 13, wherein at least part of the interior walls of the coking chamber and/or part of the surfaces of the heating elements is configured as secondary heating surfaces by coating them with a high-emission coating (HEB).
 18. The device according to claim 17, wherein the HEB consists of the substances Cr₂O₃ or Fe₂O₃ or of a mixture containing these substances, with the portion of Fe₂O₃ amounting to at least 25% by wt. in a mixture and with the portion of Cr₂O₃ amounting to at least 20% by wt. in a mixture.
 19. The device according to claim 17, wherein the HEB furthermore contains SiC with a portion of at least 20% by wt.
 20. The device according to claim 17, wherein the HEB furthermore contains one or more inorganic binding agents.
 21. The device according to claim 17, wherein the grain size of the HEB constituents is smaller than or equal to 15 μm.
 22. The device according to claim 17, wherein the walls of the flue gas channels extending horizontally underneath the coking chamber are partly or entirely coated with the HEB.
 23. A method for the production of coke by utilizing one or more coke ovens according to claim
 13. 24. A method according to claim 23, wherein the method comprises a carbonization step wherein the carbonization is carried out at a mean oven room temperature of 1,000 to 1,400° C.
 25. The device according to claim 17, wherein the grain size of the HEB constituents is between 2.5 and 10 μm. 